Summary: Informed consent will be obtained from parent/guardian and assent obtained from participant. Interested participants will have a free diagnostic evaluation by study psychiatrist to determine eligibility. Routine blood tests and a urine pregnancy test will be obtained. Eligible participants will be randomized to receive either omega-3FA or matching placebo (corn oil) for 10 weeks. Patients will be seen weekly throughout the trial. Dosage will be titrated based on clinical response and side effects. At end of double-blind phase, participants will be referred to a clinician who will be informed of subjects' treatment. Depending on treatment received during double-blind phase, post-study treatment options will include treatment with omega-3 fatty acids or an SSRI.